Characteristics of clustered cases by site of TB
| Group 1 (PTB or PTB+EPTB) | Group 2 (all patients) | |
|---|---|---|
| PTB, pulmonary TB; EPTB, extrapulmonary TB. | ||
| *Only clusters initiated by smear negative case. | ||
| †(Smear negative events/total smear negative)/(Smear positive events/total smear positive). | ||
| No. of clusters | 27 | 44 |
| Total clustered patients | 79 | 129 |
| Total secondary cases | 52 | 85 |
| No. of clusters with smear negative index cases | 6/27 (22.2%) (95% CI 12 to 31) | 18/44 (41%) (95% CI 31 to 52) |
| No. of secondary cases attributed to smear negative transmission* | 9/52 (17.3%) (95% CI 10 to 27) | 22/85 (26%) (95% CI 15 to36) |
| Relative transmission rate† | 0.21 (95% CI 0.09 to 0.38) | 0.34 (95% CI 0.21 to 0.49) |